Blade structure for turbines



P 6,1932- c. LORENZEN' 1,876,067

I BLADE STRUCTURE FOR TURBINES Filed Sept. 15. 1921 v bolted or otherwise secured to PatentedSept. 6, 1932 CHRISTIAN LORENZEN, OF BERLIN-TREPTOW, GERMANY, ASSIGNOR, BY .MESNE AS- SIGNMENTS, T0 BENDIX AVIATION CORPORATION, OF CHICAGO, ILLINOIS, A COB- ]?ORATION OF DELAWARE BLADE fsrnoorunn r03 TURBINES Application filed September 15, 1927,'Seria1 No. 219,600, and in Germany September 20, 1926.

some cases manufacturers used the expen-' sive expedient of milling or otherwise machining the turbine blades integrally with; the body of the rotor disk When separateblades were inserted in the rotor disk, they were occasionally connected with each other, but the result of such construction was that the only way of separating the blades from their carrier or rotor body consisted in first disconnecting the blades from each other.

According to the preferred form of my present invention, all the blades of the same set are connected at their heads to form a continuous annular structure at that portion, and this annular structure or body, as a unit, is set in a turbine rotor body made in separable sections. The individual blades may be either solid or hollow, and the divided rotor disk may consist either of two like, symmetrical sections, or of a rotor disk proper and a separable annular 'member or cover said disk and forming in conjunction therewith a holder for the annular series of rotor blades. Preferably the blades are connected with I each other by means of rings applied at each side of their heads, whereby a unitary structure is formed consisting of an annular set of blades connected rigidly and therefore handled readily as a unit. The rings men-' tioned above may have projecting edges (so. that in cross section the rings may be angular or U-shaped), and these edges, by their cooperation with a similar formation on the turbine stator, may form a labyrinth pack-' ing to preserve a satisfactory joint between the rotor and the stator.

Another feature of my present invention relates to'the formation of the blade feet, that is,

the blade portions nearest the axis of the rotor. According to this feature of my in- I vention, such feet are provided with lateral projections forming an annular series, either interrupted or continuous, according as-the feet of adjoining blades are out of contact or touch each other. or rings are engaged by the projecting edges of the rotor disk or portions thereof, and thus constitute means bracing the annular set of blades against the action of centrifugal force. At the same time, this construction affords a reliable means for centering the rotor blades relatively to the rotary turbine disk.

In cases where spaces intervene between portions of adjacent turbine blades, a further strengthening of the connection may be ob- These annular series tained by having the projections on the feet of the blades extend not only at opposite sides thereof, but all around, on all four sides, and providing1 the rotor body with tooth-like projections tting between adjacent blades, and engaging the transverse projecting portions of the blade feet; besides, the rotor body engages and holds the lateral projections of the blade feet, forming an interrupted or a continuous ring on each side of the set of blades. Two typical and satisfactory embodiments of my invention are shown, as examples, in the accompanying drawing, in which Fig. 1 is a partial elevation of a turbine rotor constructed according to my invention, looking lengthwise of the turbine axis; Fig. 2 is a partial axial section, taken on line 22 of Fig. 1; Fig. 3 is a partial view similar to Fig. 1 and illustrating another form of my invention; Fig. 4 is a partial section on line 44 of Figs. 3 and 5 and Fig. 5 is a section on line 5-5 of Figure' l.

In the drawingythe bodies, shanks,'working portions, or stems of the rotor blades are designated as 1, their outer ends or heads as 2, and their-inner ends or feet as 3. According to Figs. 1 and 2, the heads 2 of the adjoining blades are in contact with each other, and

connected in any suitable manner, as by weldsince the feet are out of contact in this form of my invention, form interrupted rings one of which is overlapped and held by a flange 5 on the rotor body or disk 6, while the other ring Figs. 3, 4, and 5 the heads 2, which abut end to en are connected by lateral rings 8 of U-shaped cross section, the projecting members or flanges 9 of said rings extending outwardly and cooperating with inwardly projecting rings on the stationary housing or stator 10 to form a socalled labyrinth packing. The stator rings are located in grooves of the stator 10, into which 9 extend. The feet 3, in this second form of my invention, are in mutual contact, and each foot has a flange 11 extending continuously around it, the abutting lateral or circumferential portions of the flanges 11 on adjacent feet 3 constituting the lateral rings which are overlapped and held by the inwardly-extending flanges 5 on. the two rotor sections 6,

p which are alike or'rather symmetrical, and

relatively to the rotor disk of body.

constitute the body or disk of the rotor. Each of said sections is provided, at its flangefi", with teeth 12 projecting between the shanks or stems 1 of the blades and feet 3. A very strong construction 1y, not only to resist the outward thrust of centrifugal force, but also to guard against any circumferential shifting of the blades Screw bolts and nuts 13 have been indicated in the drawingias means for holding the v vidual blades relatively cover 7 against the ody portion ofthe rotor in Figs. 1 and 2, and for holding the two rotor body sections-6 together in Figs. 3 and 4. It will be understood that other securing means might be employed for this purpose.

Upon loosening these securing means or their equivalents, the unit consisting of the connected blades 1, 2, 3 is free to be removed from the carrier formed by the rotor disk or body, andsuch removal does not involve any disturbance in the relative position of the rotor blades. Similarly, a new or repaired set ,of blades may be inserted readily as a unit,

without disturbing the position of the indito each other. This applies to both formsof my invention illustrated herein.

In the case the complete ring unit of the annular set of blades exceeds in size a cergrooves the heads 2 and their rings 8,

engaging the transverse portions of the flanges provided on the blade is thus obtained, the blades being held securerings, and a stator having tainlimit it maybe desirable to divide this unit into several segments or sections each consisting of a plurality of blades, these sections abutting as indicated at J in Fig. 1 and forming together a complete ring which may be separately-inserted into or removed from the carrier after the method des'crib. d above.

Various modifications may be ma e without departing from the nature of my invention-as defined in the claims.

I claim:

1. A turbine rotor comprising an annular set of blades each provided with a-working portion andwith an inner portion or foot having edges projectinglaterally beyond said working portion, said edges forming annular series, and a body or carrler having edge portions overlapping and holding said edges of the blade feet.

'2. A turbine rotor comprising an annular set of. blades each provided with a working portion spacedfrom theworking portions of the adjoining blades, and with an inner portion or'foot, and a body or carrier engaging and holding said feet and provided with projections or teeth extending between working portions of the blades. r

3. A turbine rotor comprising two sepa- -rable body or carrier sections and means for normally holding them together, and an annular set of blades each provided. with a working portion and with an inner portion having flanges or portions overlapping and holding the edge portions of the blade feet and being provided with projections or teeth blades.

4. A turbine rotor comprising two separable body or carrier sections and means for normally holding them together, and an annular setlof blades each provided with a wdrkingportion and with an inner portion or foot whose edge portions project lateraladjacent blades being in mutual contact and forming a continuous ring, and said carrier sections having flanges or portions overlapping and holding the edge portions of the blade feet, and being providedwith projections or teeth extending between the blades adjacent to said feet.

5. A" turbine rotor comprising an annular set'of blades each provided with an outer end portion or head, rings located at opposite sides of said heads and connecting them to hold the blades together, said rings having Q outwardly projecting flanges, a rotary body or carrier supporting said blades with their which said blade heads extend, and also having rings forming a labyrinth joint with said flanges of the blade'rings. J

3 or foot having laterally projecting edge portions in annular relation, said carrier sections 1 extending between working portions of the i .110 1y beyond said working portion, the feet of] a groove into In testimony whereof I have signed this specification.

CHRISTIAN LORENZEN. 

